Wednesday, July 16, 2014

Biochar - Cation Exchange Capacity

Without getting into the chemistry of Cation Exchange Capacity (CEC). CEC is effectively the measure of how big the bucket is for the soil to hold nutrients.

The amount of clay in a soil is typically directly related to the CEC capacity of the agricultural soils. The other significant contribution is organic matter, humus and pyrolized carbon, or bio char.

So what is the typical CEC of a good soil near Rochester, Minnesota?

A good loamy clay based soil will have a CEC of about 20.

Native prairie soils about 25.

A very active montmorillonite clay can have a CEC of 70-100.

Vermiculite can have a CEC of 100-150.

Humus or finished compost can have a CEC of  50-100

Terra Pareta (soil based on bip char) can have a CEC of 220.

The bottom line is, how do we get our soils to look like Terra Pareta, the soil based on bio char?

We are experimenting with this on our farm by making bio char on a small scale..

It will take a season to get the results. We will let you know how it turns out.

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